The purpose of this study is to determine the safety and the immune responses to the HIV vaccine candidate, MVA-CMDR. This vaccine was designed to induce immune responses to three HIV "passenger" genes encoded with the viral vector, MVA.

Any female volunteer must have a negative serum or urine pregnancy test at the screening visit as well as immediately prior to each vaccine/placebo vaccination, as well as verbal assurance that adequate birth control measures have been followed for 60 days prior to the first vaccine/placebo vaccination and will continue to be followed for at least 3months after the final vaccine/placebo vaccination. This means using any of the following methods: Birth control drugs that prevent pregnancy given by pills, shots or placed under the skin, Male or female condoms with or without a cream or gel that kills sperm, diaphragm or cervical cap with a cream or gel that kills sperm, or Abstinence

Exclusion Criteria:

A volunteer will be excluded if one or more of the following conditions apply.

A woman who:

Is pregnant.

Is breast-feeding.

Anyone who:

Is U.S. military personnel.

Acknowledges engaging in highest-risk behavior within six months of study entry

Has active tuberculosis or other systemic infectious process by review of systems and physical examination.

Has ECG on Screening Visit 2 with clinical significant findings, or features that would interfere with the assessment of myo/pericarditis (as determined by the contract ECG Lab) including any of the following: conduction disturbance (atrioventricular or intraventricular condition, left or right bundle branch block, AB block of any degree or QTc prolongation), repolarization (ST segment or T wave) abnormality, significant atrial or ventricular arrhythmia, frequent atrial or ventricular ectopy (e.g. frequent premature atrial contractions, 2 premature ventricular contractions in a row), ST elevation consistent with ischemia, or evidence of past or evolving myocardial infarction

Has history of seizure disorder, immunodeficiency, chronic illness, autoimmune disease, diabetes mellitus active malignancy or use of immunosuppressive medications.

Has evidence of psychiatric, medical and/or substance abuse problems during the past six months that the investigator believes would adversely affect the volunteer's ability to participate in the trial.

Has occupational or other responsibilities that would prevent completion of participation in the study.

Has received any live attenuated vaccine within 60 days of study entry.

Has used experimental therapeutic agents within 30 days of study entry.

Has received blood products or immunoglobulins in the past three months.

Has history of anaphylaxis or other serious adverse reactions to vaccines.